Pulse width decoder



June 21, 1960 A. T. BRENNAN 2,942,194

PULSE WIDTH DECODER ALAN T. BRENNAN grof, 57M

ATTO EY June 21, 1960 A. T. BRENNAN PULSE WIDTH DECODER Filed oci. 10, 1956 2 Sheets-Sheet 2 babbo MMDL M \o o 4 mm O N m N Y V M E TJ D I I D.. m M M M M E W T H 2 f @A A a n l ,l Z .u n D M T Jl m M w n N i ooooooododcooodocoooaodoooo OH w( 5( )H O O O O O O 5540 2 3 ures identifying corresponding elements.

'v 20, for example, to be unblocked, the grid of tap 14 must be driven in a positive direction, and/or the cathode, coupled to tap 15, must be driven in a negahve Or, the

Only a signal of a duration correspond- Signals of greater length will at tap 15, will raise the cathode of amplifier 20 an l amount equalto the rise of the grid potential, and will Y produce no change in conductance of amplifier Z0. The same comments may be made about each amplifier.

In Fig. 3, a series of graphs are shown to illustrate the relativeV positions of a pulse of microseconds duration at the several tapsV 12 to 1.7. lIf the transmission line ,v is of such a length astoproduce a'5 microsecond delay, the various positions of the pulse will occur at the sevi'eral taps asfshown. -At tap 1d, for example, the inci- `dent wave 50,A and refiected wave 5i have not met but are spaced apart bythe distance 11.

` fier 20 connected to tap 14 accordingly is not changed. i At tap 15, however, the incident and reflected waves The grid of amplihave overlapped, driving the cathode of amplifier 2@ two units of voltage in a negative direction with respect to the grid, and will thus overcome the static grid and cathode bias and will thus produce conduction and a signal at terminal 43. It will be noted, however, that taps 1S and'l, connected to the input of the next adjafcent ampliiier 21, drive the grid and cathode of 21 in `the same direction potential-wise, and are unaffected by the 5 microsecond pulse. Shortest pulses only will pass amplitier 22, while the longest pulse only `will be accepted and passed by amplifier i8. e In Fig. 2, transistors have been substituted for the triodes ofl Fig. l, like reference characters in the two fig- The NPN type transistors have been assumed with the bases connected j to the taps and the emitters connected in circuit like 1 the cathodesr, while the collectors have been connected I likethe anodes. a less'negative value than the emitters. prevent conduction through the collector circuits unless the bases'are forced positively two units of voltage with Each emitter is con- 'y Vnected to a `tap next adjacent the tap connected to its The bases are biased by source 40a to The two biases respect lto the emitter voltage.

1-base',.'so l.that the. operation is'anal'ogous to thatof the amplifiers of Fig. l. I n the particular transistor embodiment shown, the bases are biased to -3 volts, while ythe emitters are biased to 4.5 volts. The invention is, l of 'course,'not limited to such specific values.

While aspecifc embodiment of this invention has been What is claimed is:

l. pulse width discriminator comprising a transmission line so terminated at one Vend as to reflect energy Y 'and connected to the other end to a source of pulse "energy, a plurality of biased ampliers, said amplifiers each having two input electrodes, the two input electrodes of each amplifier being connected to spaced points along said line intermediate the ends of said line so that inphase portions of incident and refiected pulse waves arrive at the spaced points at difierent times.

' 2. A pulse width discriminator comprisinga transmission line, said line having a plurality of taps spaced along the line, a plurality lof amplifiers, each amplifier having y two input v terminals and an output terminal, said two terminals of each amplifier being connected to dilerent taps, and separate utilization means connected to each output terminal.

3. A pulse discriminator comprising a transmission line having a measured electrical length, said line having a plurality of taps "spaced along the line, a plurality of amplifiers, each amplifier having two input terminals and yan output terminal, each amplifier having one input terminal connected respectively to one tap, the-other input terminal Vof the amplifier being connected to the next adjacent tap, and separate output circuits connected, respectively, to the output terminals of said amplifiers.

4. The pulse dscriminator defined in claim 3, further having two biasing'sources connected, respectively, to said two input terminals.

5 The pulse discriminator defined in claim 3further comprising a'signal amplitude limiting device connected Y to one end of said transmission line.

6.'A pulse discriminator system for separating mixed pulsesyfrom a source of pulses of various lengths, into i' separate output circuits, said system comprising a delay transmission line, said line 'being adapted for connection at one end to Ysaid source of pulses and being so terminated atl the other end as to reflect all said pulses without inversion; a plurality of amplifiers, each ampliier having a first and a secondY cont-rol electrode and having means for biasing the control electrodes relative to each vother to normally cut off current in the output circuit of the amplifier, the first control electrode of said amplifiers being coupled, respectively, to different spaced intermediate points along said line so that said first control electrodes are successively biased toward conduc tion by each incident pulse, the second control electrode of said amplifiers being coupled, respectively, to spaced intermediate points along said line, theV last-mentioned points being displaced toward the terminated end of said line so that said second control electrode is biased toward non-conduction by each reflected pulse. Y

V7. A discriminator for separating pulses of various widths, said discriminator comprising a transmission line for connection at one end to a source of pulses of mixed width and Vso terminated at Vthe other end Vas to reilect said pulses toward said one end, a plurality of pulse amplifiers, each amplifier having two control 'electrodes the relative voltages of which determine conduction 'in the output of the amplifier, a irst control electrode of each amplifier being connected to an intermediate point onY said line, the connection points of the plurality of iirst control electrodes being spaced apart along said line to successively receive incident pulses from source,

the other `control electrodes of said amplifiers being contion and non-conduction of said amplifier.

soY

References Cited'in the ile of this patent UNITED STATES PATENTS 2,266,154 Blumlein Dec. 16, 1941 2,403,561 I Smith July 9, 1946 2,449,819 Purington Sept. 2l, 1948 2,511,595 Loughren June 13, 1950 2,536,032 Clark lan. 2,V 1951 2,576,617 Loughren Nov. 27, 1951 2,577,141 Mauchly et al. Dec. 4, 1951 2,631,232 Baracket Mar. l0, 1953 2,635,229 Gloess et al Apr. 14, 1953 2,670,463 Raymond Feb. 23, 1954 2,706,810 Jacobsen Apr. 19, 1955 2,707,751 Hance May 3, 1955 2,795,775 Faymoreau et al. June 11, 1957 p FOREIGN PATENTS 166,416 Austria2 e July 25, 1950 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No A942q 194 June 21 1960 Alan To Brennan It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as correo-bed below.

Column 3, line 65 for "to", first oceurrence read Signed and sealed this 15th day of November 1960,

(SEAL) Attest:

KARL H- AXLNE ROBERT c. WATSGN Attesting Officer Commissioner of"Patents 

